OEM Lennox Bottom Burner Box — 61M18
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The Lennox 61M18 (factory reference LB-100712A) is the bottom burner box that houses and positions the gas burners inside your Lennox furnace. It provides the correct combustion geometry and airflow path so the burners fire cleanly and direct heat into the heat exchanger safely. This component is a direct OEM replacement for the original bottom burner box assembly.
A damaged, corroded, or warped burner box can lead to poor flame alignment, incomplete combustion, sooting, delayed ignition, or a furnace that short-cycles on the flame sensor or rollout switch. If you notice yellow or lazy flames, unusual burner noise, or repeated safety lockouts, the burner box may be part of the problem and should be inspected.
Why OEM matters: Lennox designs the 61M18 to exact combustion tolerances specific to their furnace platforms. Aftermarket or mismatched boxes can disrupt flame travel and airflow, compromising efficiency and safety. Installing the genuine OEM part ensures proper fit, rated performance, and compliance with Lennox specifications.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days